How can we connect Tableau Software to a remote computer hosting Oracle Data Base? I achieved successfully this on my local computer by connecting Tableau to the localhost while I failed on a remote machine eventhough I can reach it by pinging.

You'll need the specific connection info in order to link Tableau with the Oracle db as localhost won't work anywhere but the machine itself. You'll likely have to grab that info from the tnsnames.ora file, or ask your admin: